The present invention relates, in general, to a drowsiness detection method. Various embodiments of the invention relate to a drowsiness detection method which can detect the heartbeat signal and breathing signal of a user without coming into direct contact with the target body of the user, can count a signal output value through signal amplification and processing of the detected signals, and can output a warning sound, voice message or vibration through an output unit in the case where a value, obtained by subtracting a counted output value which was monitored one minute before a current time, from a counted output value which was monitored two minutes before the current time, falls within a range from 2 to 10, or from −2 to −10 and where, with the passing of time, the value falling within the range from 2 to 10 or from −2 to −10 is successively detected from two to ten times within the same range.
Generally, heart rate monitors for measuring biological signals such as the heartbeat of a human body are classified into contact and non-contact types.
The most popular one of contact type monitors is a monitor using a pulse oximeter, and is implemented using a method of putting a probe on the finger of a measurement target user and detecting biological information, such as blood oxygen saturation, pulse rate, and pulse amplitude. Further, another contact type monitor uses an electrocardiograph, and is configured to attach electrodes to body regions such as the breast, wrist and ankle, measure signals and extract heartbeat information.
Such a conventional heartbeat detection method is problematic in that, since it basically uses a method of attaching a monitor or a plurality of electrodes to a part of the body of a measurement target user or putting a band with a monitor attached thereto on the part of the body, the user feels aversion and inconvenience, and in that biological signals such as a heartbeat cannot be measured unless direct contact is made with a target body.
Further, as other methods, there are conventional technologies proposed to detect biological signals such as a heartbeat in a non-contact manner. One of the conventional technologies is a patent disclosed in Korean Patent Appln. No. 10-2006-0019267 which was registered and is entitled “Remote Biological Information Detection Apparatus and Application Apparatus Thereof”. Such a patent relates to a method of measuring biological information using the principle of a Doppler radar, and is configured to obtain biological information from the variation in signals generated as a result of the motion of the internal organs of a human body.